U.S. patent number 7,677,015 [Application Number 10/631,400] was granted by the patent office on 2010-03-16 for method and apparatus for forming films.
This patent grant is currently assigned to The Procter & Gamble Company. Invention is credited to Timothy Bernard William Kroese, Rachid Ben Moussa, Kenneth Ruehl.
United States Patent |
7,677,015 |
Kroese , et al. |
March 16, 2010 |
Method and apparatus for forming films
Abstract
A process for forming filled sealed pouches, comprising:
supplying a thermoformable film to an upper surface of a conveyer
which includes a plurality of recessed vacuum molds in its upper
surface and is mounted to slide over an elongated conveyor support
through holding, forming, filling and sealing stations; holding the
film on the conveyer at the holding station; forming the film to
form pouches at the forming station by supplying a forming
under-pressure at the forming station into the mold recesses
wherein the forming under-pressure is supplied through vacuum
apertures leading from a vacuum supply apparatus and discharging
through the conveyer support through vacuum orifices extending
through the conveyer into the vacuum molds wherein under-pressure
is supplied to the mold recesses at one or more subsequent
processing stations through the vacuum apertures and vacuum
orifices, and wherein the under pressure at the forming station is
greater than the under-pressure at one or more of the subsequent
processing stations; filling the pouches at the filling station;
and sealing the pouches with a sealing film at the sealing
station.
Inventors: |
Kroese; Timothy Bernard William
(Brussels, BE), Ruehl; Kenneth (Cincinnati, OH),
Moussa; Rachid Ben (La Hulpe, BE) |
Assignee: |
The Procter & Gamble
Company (Cincinnati, OH)
|
Family
ID: |
33455764 |
Appl.
No.: |
10/631,400 |
Filed: |
July 31, 2003 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20050034432 A1 |
Feb 17, 2005 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
PCT/US02/02964 |
Jan 31, 2002 |
|
|
|
|
60265462 |
Jan 31, 2001 |
|
|
|
|
Current U.S.
Class: |
53/453;
53/559 |
Current CPC
Class: |
B65B
47/10 (20130101); B65D 85/808 (20130101); B65B
41/12 (20130101); C11D 3/3942 (20130101); C11D
17/043 (20130101); C11D 17/003 (20130101); B65B
9/04 (20130101); C11D 17/042 (20130101); B65B
9/042 (20130101); C11D 17/041 (20130101); C11D
17/046 (20130101); B29L 2031/7128 (20130101); B31B
70/10 (20170801); B29C 2791/006 (20130101); B29C
51/10 (20130101); B29L 2031/7148 (20130101) |
Current International
Class: |
B65B
47/00 (20060101); B65B 5/00 (20060101) |
Field of
Search: |
;53/559,453,266.1,467,289,292 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0 188 832 |
|
Jul 1986 |
|
EP |
|
WO 92/17382 |
|
Oct 1992 |
|
WO |
|
WO 93/08095 |
|
Apr 1993 |
|
WO |
|
Primary Examiner: Rada; Rinaldi I.
Assistant Examiner: Paradiso; John
Attorney, Agent or Firm: McKelvey; Idris N. Grunzinger;
Laura R.
Parent Case Text
CROSS-REFERENCE
This is a continuation of International Application PCT/US02/02964,
with an international filing date of Jan. 31, 2002, which claims
benefit of Provisional Application Ser. No. 60/265,462, filed Jan.
31, 2001.
Claims
What is claimed is:
1. A process for forming filled sealed pouches, comprising: a.
supplying a thermoformable film to an upper surface of a conveyer
which includes a plurality of recessed vacuum moulds in its upper
surface and is mounted to slide over an elongated conveyor support
through holding, forming, filling and sealing stations; b. holding
the film on the conveyer at the holding station; c. forming the
film to form pouches at the forming station by supplying a forming
under-pressure at the forming station into the vacuum moulds,
wherein the forming under-pressure is supplied through vacuum
apertures leading from a vacuum supply apparatus and discharging
through the conveyer support through vacuum orifices extending
through the conveyer into the vacuum moulds, wherein under-pressure
is supplied to the vacuum moulds at one or more subsequent
processing stations through the vacuum apertures and vacuum
orifices, and wherein the under pressure at the forming station is
greater than the under-pressure at one or more of the subsequent
processing stations; d. filling the pouches at the filling station;
and e. sealing the pouches with a sealing film at the sealing
station; wherein an under-pressure that is greater than
substantially zero is supplied at all of the subsequent processing
stations.
2. The process of claim 1, wherein the under pressure at the
forming station is greater than the under-pressure at all of the
subsequent processing stations.
3. The process of claim 1, wherein the vacuum apertures which lead
to the holding station and/or one or more of the subsequent
processing stations, lead from a first vacuum apparatus and the
vacuum apertures which lead to the thermoforming station lead from
a second vacuum apparatus, wherein the first vacuum apparatus
provides a lower under-pressure than the second vacuum
apparatus.
4. The process of claim 1, wherein the under-pressure in the moulds
increases gradually or stepwise from a lower under-pressure or a
substantially zero under pressure in the holding station to the
higher, forming under-pressure.
5. The process of claim 4, further comprising shaping the film at a
shaping station, wherein the shaping station is between the holding
station and the forming station and wherein the under-pressure
applied to the moulds in the shaping station is at a value
intermediate the lower or substantially zero under-pressure applied
in the holding station and the higher forming under-pressure
applied in the forming station.
6. The process of claim 1, wherein a lower under pressure is
applied to the moulds in all the stations before and subsequent to
the forming station than in the forming station.
7. The process of claim 1, wherein the film is thermoformed at the
forming station.
8. The process of claim 1, wherein the film is heated in or prior
to approaching the forming station.
9. The process of claim 1, wherein the conveyer comprises a
continuous belt which makes substantially vacuum-tight sliding
contact with the elongated conveyer support and a mould assembly
comprising the vacuum moulds and secured for movement with the belt
and wherein there are passages through the belt for transmitting
under-pressure from the vacuum apertures to the vacuum moulds.
10. The process of claim 1, wherein a series of platens comprise at
least one mould, said platens being mounted on the belt and a mould
in each platen being in vacuum contact through its associated
platen and the continuous belt with the vacuum apertures in the
conveyer support.
11. The process of claim 10, wherein the platens comprise a
plurality of moulds.
Description
TECHNICAL FIELD
This invention relates to method and apparatus for forming a film
and, in particular, to such method and apparatus wherein the film
is thermoformed into pouches which are then filled and sealed in a
sequential operation.
BACKGROUND TO THE INVENTION
Methods of forming a film are well known. An early disclosure is in
U.S. Pat. No. 3,218,776. In that method the film is thermoformed
into pouches and filled while travelling in a circular path. One
disadvantage with present systems is that it is difficult to
operate them at production speeds as high as would be desirable
while maintaining product quality. Another problem is that it is
desirable, for cost and functional reasons, to use a film which is
as thin as possible but decreasing the thickness of the film
increases the risk that the film will be undesirably weakened, and
possibly even perforated, at some points in the final product,
especially during high speed, high under-pressure, production
conditions. Another problem is that it is necessary to apply a
large vacuum (high under-pressure) and it can be difficult to
provide such a pressure efficiently in the moulds in a manner which
does not interfere with the overall operation of the process.
The object behind the invention is to solve these problems
individually and, preferably, in combination.
SUMMARY OF THE INVENTION
The apparatus according to the invention is for forming filled
pouches and it comprises: (a) a vacuum supply apparatus, (b) an
elongated conveyor support, (c) an elongated row of vacuum
apertures leading from the vacuum supply apparatus and discharging
through the conveyor support, (d) a sequence of processing stations
above the row of apertures in the conveyor support and which
comprise holding, forming, filling and sealing stations, (e) a
conveyor which includes a plurality of recessed vacuum moulds in
its upper surface and mounted to slide over the conveyor support
through each the processing station, (f) vacuum orifices extending
through the conveyor into the vacuum moulds for transferring
under-pressure from the vacuum apertures to each of the moulds, (g)
means for supplying formable sheet material on to the conveyor at
or ahead of the holding station, (h) drive means for driving the
conveyor carrying the sheet material through the processing
stations, and (i) means for supplying into the mould recesses
through the vacuum apertures and the vacuum orifices a forming
under-pressure at the forming station and at one or more subsequent
processing stations wherein the under pressure at the forming
station is greater than the under-pressure at one or more (and
preferably all) of the subsequent processing stations.
This apparatus solves the problems summarized above.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 schematically illustrates an embodiment of a process for
forming filled sealed pouches.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 schematically illustrates an embodiment of the process
according to the invention. The process comprises: a. supplying a
thermoformable film 2 to an upper surface of a conveyer 4 which
includes a plurality of recessed vacuum moulds 6 in its upper
surface and is mounted to slide over an elongated conveyor support
8 through a holding stating 10, a forming stating 12, a filling
station 14 and a sealing station 16; b. holding the film 2 on the
conveyer 4 at the holding station 10; c. forming the film 2 to form
pouches 24 at the forming station 12 by supplying a forming
under-pressure at the forming station 12 into the vacuum moulds 6,
wherein the forming under-pressure is supplied through vacuum
apertures 18 leading from a vacuum supply apparatus 20 and
discharging through the conveyer support 8 through vacuum orifices
22 extending through the conveyer 4 into the vacuum moulds 6,
wherein under-pressure is supplied to the vacuum moulds 6 at one or
more subsequent processing stations through the vacuum apertures 18
and vacuum orifices 22, and wherein the under pressure at the
forming station 12 is greater than the under-pressure at one or
more of the subsequent processing stations; d. filling the pouches
24 at the filling station 14; and e. sealing the pouches 24 with a
scaling film 26 at the sealing station 16. An under-pressure
greater than substantially zero is supplied at all of the
subsequent processing stations.
The various processing stations may merge with each other but there
may be an equilibrating station between any pair of adjacent
stations wherein the under-pressure in the equilibrating station
which merges with an adjacent processing station is at least the
under-pressure in the adjacent station which has the lower
under-pressure and is normally above the holding under-pressure.
Additionally there may be stations at which no under-pressure is
applied.
There may be a cutting station after the sealing station for
cutting the sheet of pouches into individual pouches, or into
groups of individual pouches, whilst still on the conveyor.
The apparatus may include means for heating the film in, or more
usually as it approaches, the forming station. This process is
known as thermoforming and is the preferred method of forming the
film herein.
The conveyor support can be cylindrical but preferably is a flat
support over most or (preferably) all of the processing stations.
The conveyor should be such that the vacuum moulds slide over the
conveyor in a manner that is substantially vacuum tight, so as to
prevent undesirable loss of vacuum.
It is generally necessary to grip the edges of the film at the
holding and forming stations to prevent the edges being drawn
inwardly. This can be by mechanical grips or resilient bands, as is
conventional, or by other means.
It is desirable in the invention to achieve the forming
under-pressure gradually or stepwise and to release it gradually or
stepwise. This reduces the risk of damage to the film and minimises
the risk of crinkles in the film, even when the film is thin.
In particular, it is desirable to apply an under-pressure to some
or all of the processing stations to a value which is considerably
smaller than the high forming under-pressure. Designing the vacuum
apertures in such a way as to achieve this while using a single
vacuum supply apparatus tends to be rather inefficient and so
preferably the vacuum apertures which lead to the holding station
and/or to one or more of the subsequent processing stations lead
from a first vacuum apparatus and the vacuum apertures which lead
to the forming station lead from a second vacuum apparatus, wherein
the first vacuum apparatus is a higher volume, lower
under-pressure, apparatus for applying a lower under-pressure and
the second apparatus is a lower volume, higher under-pressure,
apparatus for applying the forming under-pressure at the forming
station. As an example the first vacuum apparatus can be a simple
vacuum pump, or even a fan, or other apparatus designed, for
instance, to remove most of the air fast from the holding station
at a large air flow but under a low under-pressure, and the second
vacuum apparatus can be a vacuum chamber constructed to give a high
forming under-pressure, but with only relatively small amounts of
air being removed. The first vacuum apparatus may be used to supply
vacuum to some (or all) of the subsequent processing stations
and/or the second vacuum apparatus may be used for this purpose,
depending upon the under-pressure required at each station. The
under-pressure in the holding station can be substantially zero, by
which we mean it is just sufficient to hold the film down against
curling, but preferably it is greater than this.
It is desirable that the under-pressure does not increase too
rapidly from the holding under-pressure up to the forming
under-pressure, since this is liable to promote wrinkling or
undesirable local damage to the film. Preferably therefore the
overall vacuum supply apparatus (generally the second vacuum supply
apparatus) and the vacuum apertures are so constructed that the
under pressure in the moulds increases gradually or stepwise from
the lower under-pressure (in the holding station) to the higher,
forming under-pressure. The increase may be gradual over a duration
which can be, for instance, 0.5 to 5 times, often 1 to 3 times, the
duration for which the forming under-pressure is applied.
Generally there is a shaping station between the holding and
forming stations. The vacuum supply apparatus and the vacuum
apertures preferably are so constructed that the under-pressure
applied to the moulds in the shaping station is at a value
intermediate the lower under-pressure applied in the holding
station and the higher forming under-pressure applied in the
forming station. If desired, the shaping station may include a
sequence of two or more stations with a higher under-pressure in
each station than in the preceding station. The high forming
under-pressure is preferably applied only for the time necessary to
achieve forming and so preferably the vacuum supply apparatus and
the vacuum apertures are so constructed that a lower under-pressure
is applied to the moulds in, usually, all the subsequent processing
stations (including any equilibrating stations) prior to and
subsequent to the forming station. This under-pressure can be as
low as the under-pressure applied in the holding station, but is
usually higher than this.
The ability to apply a lower under-pressure after the forming
station means that the vacuum pumps can have lower power
consumption, there is less friction between sliding and fixed
parts, less power is needed to move the conveyor and there is less
risk of damage to the pouches and, consequently, less risk of
leakage from the pouches.
The high forming under-pressure is generally applied less than 30%,
and preferably less than 25%, and generally less than 20%, of the
total time during which vacuum is applied to the moulds while
travelling on the conveyor support. Usually the duration is at
least 3%, and often at least 5 to 8% of the total time. Preferably
it is around 10 to 15% of the total time.
The highest under-pressure which is applied to the moulds at
stations other than the forming station is usually less than 80%,
and preferably less than 70% (e.g., 40 to 70%) of the forming
under-pressure. For instance, if the forming under-pressure is -500
mbar, the highest under-pressure at other stations is preferably
-400 mbar and most preferably -350 mbar, or less. The
under-pressure applied at the holding station is generally from 5
to 30%, often around 10 to 25%, of the forming under-pressure.
Typically the forming under-pressure is in the range -300 to -900
mbar, often around -400 to -700 mbar, the under-pressure in the
holding station is -40 to -150 mbar and the under-pressure in the
shaping station (if present) and in the filling and sealing
stations is from -100 to -500 mbar, often around -200 to -400
mbar.
The elongated row of vacuum apertures may be one or more elongated
slots which extend the length of the conveyor support but which are
divided transversely to allow differing under-pressure to be
applied to differing stations. Generally, however, the open area of
the apertures is greatest where the under-pressure is to be
greatest and least where the under-pressure is to be least. The
open area can be selected either by varying the number of apertures
or by varying the diameter of the apertures, or both.
The conveyor preferably comprises a continuous belt and a mould
assembly wherein the belt makes substantially vacuum-tight sliding
contact with the support and the mould assembly is secured for
movement with the belt, and wherein there are passages through the
belt for transmitting under-pressure from the vacuum apertures to
the moulds. Thus, as the belt moves over the conveyor support, it
maintains a vacuum-tight seal between the support and the belt but
carries the mould assembly in sequence from one processing station
to the next and allows the selected under-pressure to be applied
through the belt to the moulds in each processing station. This
arrangement allows for simple design and construction for the
provision of variable under-pressure to the different stations.
The mould assembly preferably comprises a series of platens which
are mounted on the belt, and mould plates which contain the vacuum
moulds in their upper surface and which are mounted in the platens
with the mould plates in vacuum contact through the platens and the
continuous belt with the vacuum apertures in the conveyor support.
Thus the belt not only seals between the belt and the conveyor
support but also seals against adjacent platens and mould
plates.
Since only a relatively short part of the travel of the belt is
subjected to the highest under-pressure, the drag between the belt
and the conveyor support (due to the under-pressure) is
minimised.
The apparatus may be constructed to operate with stepwise motion,
whereby the pouches move into a station, are treated appropriately
in that station while stationary, and then move to the next
station, with the duration in each station preferably as indicated
above. However the invention is of particular value when the
apparatus includes means for driving the conveyor, carrying the
mould plates, and thus the pouches, continuously through the
processing stations.
The film which is to be formed may be any suitable polymeric film.
Preferably the film is thermoformable. The film can for example be
obtained by casting, blow-molding, extrusion or blow extrusion. The
polymer preferably has a weight average molecular weight of from
about 1000 to 1,000,000, or even from 10,000 to 300,000 or even
from 15,000 to 200,000 or even from 20,000 to 150,000. Preferred
polymer copolymers or derivatives thereof are selected from
polyvinyl alcohols, polyvinyl pyrrolidone, polyalkylene oxides,
(modified) cellulose, (modified) cellulose-ethers or -esters or
-amides, polycarboxylic acids and salts including polyacrylates,
copolymers of maleic/acrylic acids, polyaminoacids or peptides,
polyamides including polyacrylamide, polysaccharides including
starch and gelatine, natural gums such as xanthum and carragum.
Preferably, the polymer is selected from polyacrylates and acrylate
copolymers, including polymethacrylates, methylcellulose, sodium
carboxymethyl-cellulose, dextran, maltodextrin, ethylcellulose,
hydroxyethyl cellulose, hydroxypropyl methylcellulose; most
preferably polyvinyl alcohols, polyvinyl alcohol copolymers and/or
hydroxypropyl methyl cellulose (HPMC).
Most preferred are materials which are water-soluble stretchable
and elastic material comprising PVA polymer having properties such
as for example, available from Nordenia, Aquafilm, Kuraray,
Chris-Craft Industrial Products. Typically it has a thickness of
from 10 to 100 .mu.m.
The size of the pouches is typically from 5 to 200 mls, often
having an upper surface area of 1 to 100 cm.sup.2 and a depth of
from 1 to 100 mm. The pouches can consist of a single chamber or of
multiple chambers.
The pouches are sealed by bonding another film across the top of
the sheet of pouches while it is still supported on the conveyor,
the bonding either being by adhesive, solubilisation of the surface
of the pouch film or the sealing film or both, or by thermal
adhesion or by a combination. Preferably the bonding is by a
combination of solvent welding and thermal adhesion.
The filling for the pouches may be solid or liquid and may be a
gel. Preferably the pouches are to dissolve when added to water, in
which event the sealing film or the pouch film, and preferably both
films, dissolve or disintegrate in water. The filling for the
pouches may be, for instance, a laundry detergent, dishwashing
composition, fabric softener composition, bleaching composition or
beauty care composition.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred apparatus herein comprises a vacuum supply apparatus
the top of which is defined by a conveyor support through which a
plurality of vacuum apertures extend from a vacuum box to which
suction can be applied by a pump. There are smooth low friction
strips extending along the sides of the support. These strips can
be made of polyurethane or other suitable low friction material.
They are firmly secured to the support. A belt (preferably made
from smooth impermeable material such as steel) slides over the
strips making a substantially vacuum-tight seal with them. The belt
has apertures extending through it, and these may be arranged in
the same pattern as the aforementioned vacuum apertures or in any
other suitable pattern whereby vacuum can be applied from the
vacuum apertures through the belt. The present apparatus includes a
platen plate that has a base and side rails, the base having
apertures corresponding to the apertures in the steel plate. Chains
are driven by a drive mechanism and pins transmit the drive between
the chains and the side rails of the platen plate. The belt is
driven by a wheel on the same drive mechanism. The belt and the
chains are inextensible, whereby the belt and the platens move with
one another and have intermeshing faces which are sufficiently
smooth that they are in substantially vacuum-tight
inter-engagement. Thus, rotation of the mechanism causes the belt
to move in a vacuum-tight manner over the support and causes the
platens to move in a vacuum-tight manner with the belt. The
individual platens are separated from one another and are
positioned on the belt such that there is no aperture extending
through the belt at positions between the platens. Each platen has
an inwardly inclined side rail on each side. A mould plate having
correspondingly shaped edges is slidably fixed between these
inwardly inclined side rails. A vacuum chamber is defined between
the upper surface of the platen and the lower surface of the mould
plate. There are mould recesses in the upper surface of the mould
plate and vacuum orifices leading into the base of the mould
recesses, to transmit vacuum from the vacuum chamber which, in
turn, is provided with an appropriate under-pressure by vacuum
applied through the vacuum passages. The apparatus works by feeding
a sheet of formable film material continuously from roll down on to
the upper surface of the mould plate and the side rails of the
platens, and is secured along the edges by appropriate side grips,
for instance in conventional manner. The film is then carried on
the mould plate to the holding station at which the film is
initially held tight across the upper surface of the moulds and
then these moulds are evacuated to provide an under-pressure of,
for instance, -100 mbar, with only some stretching of the film down
into the individual moulds. For this purpose, large central vacuum
apertures and the smaller side vacuum apertures lead to a dedicated
chamber and through a duct into an evacuating pump designed
predominantly to remove large amounts of air rapidly. As the moulds
move along the conveyor they are subjected to a higher
under-pressure, for instance -300 mbar, as they reach the shaping
station in which the film is deformed into approximate, but not
total, conformity with the inner shape of the mould. As the film
travels from the holding station to the shaping station it is
heated by heaters to the thermoforming temperature. For instance,
depending upon the film, the film may be heated to a temperature of
50.degree. C. to 180.degree. C. The film then reaches the forming
station and it is at this station that the maximum under pressure
is applied to the moulds, typically -400 mbar. At this stage total
conformation of the film to the mould surface is achieved. A lower
under-pressure is applied to the film in the moulds at all
subsequent positions. Typically, the formed pouches are allowed to
cool, and the pressure is maintained here at a value less than the
thermoforming under-pressure, typically -300 mbar. After the
cooling stage, the film may move through a filling station where it
is filled in conventional manner with product such as liquid
detergent. The film and pouches then travel through a sealing
station where a second layer of film is brought down on to the film
around the pouches and is pressed against it by suitable pressing
means under conditions whereby the upper layer seals to the parts
of the film extending over the upper surface of the mould plate.
The assembly can then pass through a cutting station where the
pouches are cut from one another by conventional means. Typically
the duration of the travel through the holding station is 0.5 to 5
seconds, often around 2 seconds, and the duration in each of the
shaping and forming is from 0.2 to 3 seconds. The pouches can then
be tipped out of the moulds and collected or packed. The conveyor
support can be provided with a combination of large vacuum
apertures and smaller vacuum apertures through the area extending
from the holding station and the forming station, and then only
with the smaller vacuum apertures in the subsequent areas. One
vacuum apparatus can provide the vacuum for each of the stations
where a vacuum is required. By this means it is possible to
optimise the under-pressure to each processing station and to
control the process generally, minimising the drag between the
stationary conveyor support and the sliding conveyor.
* * * * *